This invention relates to joining of thermoplastic liners and, more particularly, to mechanical connections for joining sheets of thermoplastic liners.
It is known in the prior art to use lined trenches to contain contaminated materials. After a suitable trench is excavated, a layer of an impermeable material, often a bentonite/cement slurry, is disposed in the trench. Thereafter, vertical thermoplastic curtain walls are forced into the impermeable layer and propped against the vertical walls of the trench to prevent transverse seepage of contaminants into the surrounding soil.
Different curtain wall designs are known in the prior art. Once such design is manufactured by Geotechnics Holland BV and sold under the tradename "GEOLOCK". With the "GEOLOCK" system, adjoining wall sections are secured together through a "tongue and groove" locking system which includes cooperating male and female locking members. Each wall section is formed with a rectangular panel to which a male locking member is welded along one longitudinal edge thereof and a female locking member along the other longitudinal edge thereof. In forming the curtain wall, a first wall section is slipped vertically into the trench, with consecutive wall sections being sequentially slipped into the trench with the locking members being engaged. Also, a single bead of sealant material is disposed in each of the locking joints to seal the respective joints.
This system, however, suffers from some drawbacks. First, two different types of locking members, male and female, must be provided for the system. The locking members are formed separately from the thermoplastic panels and, thus, two separate inventories of the male and female locking members must be maintained. Also, some care must be taken to ensure a male locking member and a female locking member are arranged to cooperate at each joint. A second drawback of the system is that only a single bead of hydrophilic rubber may be disposed in each of the locking joints.
A second type of curtain wall system is shown in U.S. Pat. No. 5,497,097 to Walling, et al., issued Mar. 5, 1996 and entitled "APPARATUS FOR DETECTING A CONNECTION BETWEEN ADJACENT PANELS OF A CURTAIN WALL". With this system, homogamous locking members are provided with each having protruding T-shaped locking elements which are formed to interlock. In forming a joint, the T-shaped elements are interdigitated and a plurality of beads of sealant material are disposed between the various T-shaped locking elements. The interconnection of the T-shaped elements alone, however, does not completely restrict relative movement of the joined locking members since the interdigitated T-shaped locking elements are spaced apart. The sealant material is not only used to seal the locking joint but is also required to provide stability to the joint.
It is an object of the subject invention to provide a thermoplastic curtain wall system formed with homogamous locking strips which provide stable, rigid interconnections between adjoining wall sections.
It is another object of the subject invention to provide a thermoplastic curtain wall system having wall sections connected by joints which can accommodate more than one bead of sealant material.